Door construction for shielded room



April 8, c. R. SCHALLER, JR 3,437,735

DOOR CONSTRUCTION FOR SHIELDED ROOM Sheet Filed Sept. 21, 1966 INVENTOR. CLARENCE RANDALL SCHALLER, Jf

April 1969 c. R. S'CHALLER, JR 3,437,735

DOOR CONSTRUCTION FOR SHIELDED ROOM Filed Sept. 21. 1966 Sheet ,2 .of 2

1 N VEN TOR.

ATTORNEYS.

CLARENCE RANDALL SCHALLER,JR.

United States Patent 3,437,735 DOOR CONSTRUCTION FOR SHIELDED ROOM Clarence Randall Schaller, Jr., Huntingdon Valley, Pa., assignor to Ace Engineering & Machine Co., Inc., Huntingdon Valley, Pa., a corporation of Pennsylvania Filed Sept. 21, 1966, Ser. No. 580,983 Int. Cl. Hk 9/00 U.S. Cl. 174-35 3 Claims ABSTRACT OF THE DISCLOSURE A doorway construction for a radio-frequency shielded enclosure is disclosed in which the door frame is provided with a conductively surfaced recess of truncated wedge-shaped cross-section which completely frames the doorway. The door has a wedgeshaped conductivelysurfaced projection along its four edges which is received into the recess in the door frame when the door is pivotally closed. Spring leaf wiping fingers of conductive material are secured to the sloping surface of either the wedgeshaped recess or projection for making good wiping contact with the other sloping surface.

This invention relates to a shielded enclosure adapted to exclude from the enclosure interfering radio-frequency energy whose source is external to the enclosure and to keep within the enclosure radio-frequency energy whose source is within the enclosure.

The shielded enclosure is made of material having good electrical conducting properties. It may preferably be made of wood or steel covered with a covering of nonferrous material, preferably copper. The enclosure is constructed in such manner that all joints are of low resistance.

The present invention is directed particularly to an improved door construction for such a shielded enclosure. When the improved door is in closed position, a positive electrical contact between the door and the door frame is obtained, thereby assuring that the enclosure will function as an effective radio-frequency shield.

The purpose of the present invention is to provide an improved door construction for a shielded room.

The invention will be clearly understood from the following detailed description of several preferred embodiments illustrated in the drawing in which:

FIG. 1 is a front elevational view of the door, with a corner portion of the door broken away to reveal the door frame;

FIG. 2 is a horizontal sectional view showing the door, a portion of the door frame, and the interfitted wedges and recesses of the door and door frame, respectively, as seen looking down along the line IIII of FIG. 1 in the direction of the arrows;

FIG. 3 is a vertical sectional view of the sill showing the lower wedge of the door interfitted into the recess of the sill below the threshold, as seen looking along the line III III of FIG. 1 in the direction of the arrows;

FIG. 4 is an elevational view of a corner portion of the inside face of the door showing the spring contact fingers on each sloping side of the door wedge;

'FIG. 5 is a view showing an alternate embodiment in which the spring contact fingers are secured to the sloping sides of the recess of the door frame instead of to the sloping sides of the door wedge;

FIG. 6 shows another alternate embodiment in which one spring contact finger is atached to the innermost or fiat portion of the recess and another spring contact finger is attached to the inner face of the door adjacent the wedge for contacting the outer face of the door frame at the edge of the recess;

FIGS. 7 and 8 are views in section of still another alternate embodiment in which resilient metallic woven gaskets of electrically good conductive material are used in lieu of the spring contact fingers;

FIG. 9 is a perspective view of a portion of one of the spring contact fingers; and

FIG. 10 is a perspective view of a portion of one of the resilient metallic woven gaskets.

Referring now to the drawing, the door, which is identified by the reference numeral 50, is pivotally mounted, as by hinges 51, 52 and 53, on the door frame, identified by the reference numeral 20.

In accordance with the present invention, the door frame 20 is provided along each of its edge portions (top, bottom and two sides), with a wedge-shaped depression or recess 21, preferably a truncated wedge-shape. At the four corners of the door frame, the truncated wedge-shaped recesses are mitered and joined together, forming a continuous recess which frames the doorway.

The door frame 20 and door frame recess 21 are covered with a continuous sheeting 23, preferably of copper or brass, but which could be aluminum or steel or other conductive material.

The door 50 is made of a wood panel 54 having on its inner and outer faces coverings 55 and 56, preferably be copper, brass, aluminum or other conductive material. Secured to the inner face of the door panel 54, along its four edges, are wedges 57, preferably of truncated Wedge shape, which are mitered and joined together to form a continuous truncated wedgeshaped projection which frames the inner face of the door.

The wedges 57 and the adjacent corner portions of the door are capped with a sheeting 59, preferably copper, but which could be brass, steel, aluminum or other conductive material.

In the embodiment shown in spring contact fingers or beryllium copper, of the wedges 57.

As illustrated in FIG. 2, when the door 50 swings on its hinges 51, 52, 53, from an open position, shown in phantom in FIG. 2, to the closed position, the projecting wedges 57 enter the recesses 21 of the door frame and the leaf spring contact fingers 58 make wiping contact with the sloping side walls of the recesses 21, thereby providing good electrical contact. FIG. 9 depicts a fragmentary portion of one of the leaf spring contact fingers as previously indicated may preferably be of FIGS. 2, 3, and 4, leaf 58 preferably of Phosphor bronze are secured to the sloping sides good electrical conductivity. The contact fingers 58 preferably have a serrated or toothed edge, as

shown in FIGS. 4 and 9.

FIG. 5 depicts an alternative embodiment in which the leaf spring contact fingers 58 are secured to the sloping walls of the recess 21 rather than to the sloping walls of the wedges 57.

In FIG. 6, one leaf spring contact finger 58 is shown to be secured to the innermost wall or bottom of the recess 21, rather than to the side walls, and a second leaf spring contact finger 58 is secured to the inner face of the door panel adjacent the wedge and in a position to make con tact with the corner portion of the door frame. In the embodiment of FIG. 6, the contact action is almost solely one of compression, as distinguished from the wiping action which occurs in the embodiments of FIGS. 3 and 5.

FIGURE 7 represents yet another alternative embodiment in which the leaf spring fingers 58 are replaced by a resilient metallic woven gasket 158 of electrically good conductivity, such as is illustrated in FIG. 10. In

3 FIGURE 7, one gasket 158 is secured, as by rivets, to the innermost or botom portion of the recess 21, and a second gasket 158 is secured to the inner face of the door panel adjacent the wedge 57.

In FIGURE 8, gaskets 158 are secured to the side walls 5 of the wedge 57.

It will be seen that the present invention provides, for a shielded room, a doorway construction characterized by a continuous wedge-shape conductive-surface projection secured to the door at or near its four edges on that face of the door which faces inwardly towards the doorway, and a continuous wedge-shaped conductive surface depression or recess in the door frame and framing the doorway. The projecting wedge and the wedge recess are so positioned relative to each other that when the door closes the projecting wedge fits into the recess. Resilient contact means of good electrical conductivity, preferably conductive leaf-spring fingers, or, alternatively, resilient woven metallic conductive gasket material, is fixed either to the projecting wedge and/ or to the wedge/ shaped recess, for assuring good electrical contact between the door and the door frame when the door is closed. In some of the embodiments, the resilient contact means are fixed to the sloping sides of the projecting wedge, or to the sloping walls of the wedge recess so that when the door is being closed a wiping contact is effected between the door and the door frame. In other embodiments, the resilient contact means are merely compressed, without a wiping action.

While the preferred embodiments of this invention have been described in some detail it will be obvious to one skilled in the art that various modifications may be made without departing from the invention as hereinafter claimed.

What is claimed is:

1. A doorway construction for a closure comprising:

(a) a door;

(b) a door frame,

(c) said door and door frame having surfaces of good electrical conductivity;

radio-frequency en- (d) hinge means supporting said door pivotally on said door frame;

(e) mating elements of truncated wedge-shaped crosssection on said door and door frame,

(f) said mating elements comprising:

(i) a conductively-surfaced recess in said door frame of truncated wedge-shaped cross-section completely framing said doorway;

(ii) a conductively-surfaced projection on said door of correspondingly truncated wedge-shaped cross-section located to be received into the recess in the door frame when the door is pivotally closed;

(g) resilient material of good electrical conductivity secured to the sloping surfaces of one of said mating elements for making Wiping electrical contact with the, sloping surfaces of the other of said mating elements when said door is pivotally closed.

'2. A doorway construction according to claim 1 characterized in that said resilient material comprises leaf spring wiping fingers secured to the sloping surfaces of said door projection.

3. A doorway construction according to claim 1 characterized in that said resilient material comprises leaf spring wiping fingers secured to the sloping surfaces of said door frame recess.

References Cited UNITED STATES PATENTS 3,055,969 9/1962 Schaller 3,219,747 11/1965 MeAdams.

3,321,604 5/1967 'Stecca et al. 219-1055 FOREIGN PATENTS 909,009 10/1962 Great Britain. DARRELL L. CLAY, Primary Examiner.

US. Cl. X.R. 

